5 research outputs found
Neutrino oscillations in a Robertson-Walker Universe with space time foam
In Phys. Rev. D77 (2008) 105001, we have studied decoherence models for
flavour oscillations in four-dimensional stochastically fluctuating space times
and discussed briefly the sensitivity of current terrestrial and astrophysical
neutrino experiments to such models. In this addendum we extend these results
to incorporate the effects due to the expansion of the Universe, so that our
analysis can be useful in studies of extragalactic high-energy neutrinos, such
as those coming from Gamma Ray Bursts at cosmological distances. Unfortunately
for some microscopic models of foam, constructed in the string theory
framework, we arrive at pessimistic conclusions about the detectability of the
decoherence effects via flavour oscillation meaurements.Comment: Addendum to Phys. Rev. D77 (2008) 10500
Schwinger-Dyson approach for a Lifshitz-type Yukawa model
We consider a 3+1 dimensional field theory at a Lifshitz point for a
dynamical critical exponent z=3, with a scalar and a fermion field coupled via
a Yukawa interaction. Using the non-perturbative Schwinger-Dyson approach we
calculate quantum corrections to the effective action. We demonstrate that a
first order derivative kinetic term as well as a mass term for the fermion
arise dynamically. This signals the restoration of Lorentz symmetry in the IR
regime of the single fermion model, although for theories with more than one
fermionic species such a conclusion will require fine-tuning of couplings. The
limitations of the model and our approach are discussed.Comment: 20 pages, 2 figure
Neutrino oscillations in a stochastic model for space-time foam
We study decoherence models for flavour oscillations in four-dimensional
stochastically fluctuating space times and discuss briefly the sensitivity of
current neutrino experiments to such models. We pay emphasis on demonstrating
the model dependence of the associated decoherence-induced damping coefficients
in front of the oscillatory terms in the respective transition probabilities
between flavours. Within the context of specific models of foam, involving
point-like D-branes and leading to decoherence-induced damping which is
inversely proportional to the neutrino energies, we also argue that future
limits on the relevant decoherence parameters coming from TeV astrophysical
neutrinos, to be observed in ICE-CUBE, are not far from theoretically expected
values with Planck mass suppression. Ultra high energy neutrinos from Gamma Ray
Bursts at cosmological distances can also exhibit in principle sensitivity to
such effects.Comment: 12 pages RevTex4, no figure
Black Holes in Ho\v{r}ava Gravity with Higher Derivative Magnetic Terms
We consider Horava gravity coupled to Maxwell and higher derivative magnetic
terms. We construct static spherically symmetric black hole solutions in the
low-energy approximation. We calculate the horizon locations and temperatures
in the near-extremal limit, for asymptotically flat and (anti-)de Sitter
spaces. We also construct a detailed balanced version of the theory, for which
we find projectable and non-projectable, non-perturbative solutions.Comment: 17 pages. v2: Up to date with published version; some minor remarks
and more reference